In the past, paste-like bonding agents have been mainly used to bond semiconductor chips and semiconductor chip supporting members. However, when paste-like bonding agents were used, there were problems such as defects in which the adhesives exuded out from semiconductor chips or the semiconductor chips were bonded at an angle, and difficulty in controlling a thickness of the film made of the paste-like adhesives.
In order to solve these problems, film-like bonding agents have recently received attention as a possible replacement for paste-like bonding agents (for example, see Patent Literatures 1 to 3 below). As a method of using these film-like bonding agents, there is a wafer rear side attachment method. In the wafer rear side attachment method, a film-like bonding layer is attached to a rear side of a semiconductor wafer first, and then a base sheet for dicing in which an adhesive layer is formed is attached to the other side of the bonding layer. Thereafter, a semiconductor wafer is diced to obtain individually divided semiconductor chips. The individually divided semiconductor chips are picked up and transferred to a bonding step. Therefore, the adhesive layer of the base sheet for dicing requires an adhesive strength sufficient to prevent the bonding layer from being scattered by the load created by the cutting of the semiconductor wafer, and also requires that, during picking up of semiconductor chips, adhesive residue is not present in each semiconductor chip and the semiconductor chip bonded to the bonding layer can be easily picked up.
Also, a dicing tape used for the wafer rear side attachment method includes a UV-type tape and a pressure-sensitive-type tape. A UV-type dicing tape has an adhesive strength required for dicing before UV irradiation but which allows semiconductor chips to be detached so as to be easily picked up after UV irradiation. In the case where a pressure-sensitive dicing tape is used, UV irradiation is unnecessary. However, the tape should have a combination of opposite adhesive characteristics so as to have the adhesive strength required in dicing and also have the adhesive strength weak enough to allow semiconductor chips to be easily picked up.